The present invention relates generally to differential mechanisms which provide two output speeds for a single input speed, the output speeds being variable relative to one another. More particularly, the present invention concerns a differential mechanism which can accept a linear input to regulate the two relative output speeds.
Typical differential mechanisms that have been available in the past suffer from some problems and disadvantages which are undesireable, particularly where a solution exists which will obviate those problems and disadvantages. For example, one problem associated with the known differential devices concerns their behaviour when used to drive two wheels of a vehicle over a slippery surface. If one of the two wheels should slip, then that wheel spins and the other wheel does not receive any power. As a result, the vehicle being driven by those two wheels does not move forward, at least not in a controlled fashion.
In situations where such spinning of one wheel has commenced, there are subsequent problems. Often, the spinning wheel digs itself into underlying ground, mud, or sand dispersing the material of that underlying surface and creating a depression whIch contains the wheel. That depression further aggravates the difficulty in getting the vehicle moving again in a controlled, forward direction. In addition, the friction generated between the spinning wheel and the underlying surface generates significant amounts of heat which can, and does, burn the rubber material of the associated tire leading to significantly reduced tire life.
Another shortcoming of the known systems relates to the manner in which a vehicle associated with the differential is steered. Virtually all of the known systems use an auxiliary device to steer the vehicle. The differential is used merely to permit the drive wheels to turn corners without sliding when ground traction is reasonably consistent. In such arrangements, the auxiliary device offers no assistance to overcome the problems noted above. Moreover, there exists the additional complexity and expense of the steering device.